Can't determine accurate WAN Address!?

I'm new at the whole network thing and I think I'm starting over my head. Can someone please help?
Attempting to set up a VPN...
Location 1: 4WinXP Desktops - rvs4000 Router - Westell 2100 Modem - Verizon DSL
Location 2: 1WinXP Desktop - wrvs4400n Router - DW6000 Satellite Modem - (now) Hughesnet was Earthlink by Direcway.
I believe the primary problem is that I can't determine the wan IP. The DW6000 has a Router IP and a NAT IP, plus my router has a wan IP. Maybe I need to modify settings on modems? I currently have access to internet from all computers to internet and access to and from all computers in local 1. I can't connect local 1 to local 2 or back.